<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>

<body>

</body>


<script>
  //js数据类型？
  //基本数据： Number String Boolean Null Undefined 
  //引用数据： Array Object Function

  console.log(typeof 123) // number
  console.log(typeof '123') //string
  console.log(typeof true) //boolean
  console.log(typeof null)//object
  console.log(typeof undefined) //undefined
  console.log(typeof Symbol)//function
  console.log(typeof [2, 1]) //object
  console.log(typeof { name: '123' })//object
  console.log(typeof function a123() { })//function

  // console.log([2, 1] instanceof Array)
  console.log(Symbol instanceof Symbol)//
  // console.log(Array.isArray({name:'123'}))

</script>

</html>